[RFC v2 13/14] eal: check for hugefile path overflow

[Stephen Hemminger]

When constructing huge filename path, check for possible
overflow of PATH_MAX.

Signed-off-by: Stephen Hemminger <stephen at networkplumber.org>
---
 lib/eal/common/eal_filesystem.h | 10 ++++++----
 lib/eal/linux/eal_memalloc.c    | 11 +++++++++--
 lib/eal/linux/eal_memory.c      |  9 +++++++--
 3 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/lib/eal/common/eal_filesystem.h b/lib/eal/common/eal_filesystem.h
index 5371d9f1d6..006d2ff3e5 100644
--- a/lib/eal/common/eal_filesystem.h
+++ b/lib/eal/common/eal_filesystem.h
@@ -93,12 +93,14 @@ eal_hugepage_data_path(void)
 
 /** String format for hugepage map files. */
 #define HUGEFILE_FMT "%s/%smap_%d"
-static inline const char *
+static inline __rte_warn_unused_result const char *
 eal_get_hugefile_path(char *buffer, size_t buflen, const char *hugedir, int f_id)
 {
-	snprintf(buffer, buflen, HUGEFILE_FMT, hugedir,
-			eal_get_hugefile_prefix(), f_id);
-	return buffer;
+	if (snprintf(buffer, buflen, HUGEFILE_FMT, hugedir,
+		     eal_get_hugefile_prefix(), f_id) >= (int)buflen)
+		return NULL;
+	else
+		return buffer;
 }
 
 /** define the default filename prefix for the %s values above */
diff --git a/lib/eal/linux/eal_memalloc.c b/lib/eal/linux/eal_memalloc.c
index 1e60e21620..d9e8ea76b9 100644
--- a/lib/eal/linux/eal_memalloc.c
+++ b/lib/eal/linux/eal_memalloc.c
@@ -260,6 +260,7 @@ get_seg_fd(char *path, int buflen, struct hugepage_info *hi,
 {
 	int fd;
 	int *out_fd;
+	const char *huge_path;
 	struct stat st;
 	int ret;
 	const struct internal_config *internal_conf =
@@ -276,12 +277,18 @@ get_seg_fd(char *path, int buflen, struct hugepage_info *hi,
 
 	if (internal_conf->single_file_segments) {
 		out_fd = &fd_list[list_idx].memseg_list_fd;
-		eal_get_hugefile_path(path, buflen, hi->hugedir, list_idx);
+		huge_path = eal_get_hugefile_path(path, buflen, hi->hugedir, list_idx);
 	} else {
 		out_fd = &fd_list[list_idx].fds[seg_idx];
-		eal_get_hugefile_path(path, buflen, hi->hugedir,
+		huge_path = eal_get_hugefile_path(path, buflen, hi->hugedir,
 				list_idx * RTE_MAX_MEMSEG_PER_LIST + seg_idx);
 	}
+	if (huge_path == NULL) {
+		EAL_LOG(DEBUG, "%s(): hugefile path truncated: '%s'",
+			__func__, path);
+		return -1;
+	}
+
 	fd = *out_fd;
 	if (fd >= 0)
 		return fd;
diff --git a/lib/eal/linux/eal_memory.c b/lib/eal/linux/eal_memory.c
index 8e1763e890..2a0a441398 100644
--- a/lib/eal/linux/eal_memory.c
+++ b/lib/eal/linux/eal_memory.c
@@ -337,8 +337,13 @@ map_all_hugepages(struct hugepage_file *hugepg_tbl, struct hugepage_info *hpi,
 
 		hf->file_id = i;
 		hf->size = hugepage_sz;
-		eal_get_hugefile_path(hf->filepath, sizeof(hf->filepath),
-				hpi->hugedir, hf->file_id);
+		if (eal_get_hugefile_path(hf->filepath, sizeof(hf->filepath),
+					  hpi->hugedir, hf->file_id) == NULL) {
+			EAL_LOG(DEBUG, "%s(): huge file path '%s' truncated",
+				__func__, hf->filepath);
+			goto out;
+		}
+
 		hf->filepath[sizeof(hf->filepath) - 1] = '\0';
 
 		/* try to create hugepage file */
-- 
2.51.0